The present invention relates in general to a method of measuring blood clotting ability, that is, the tendency of a patient to bleed, and more particularly, to a method which provides accurate quantitative information of blood clotting ability and bleeding tendency of the patient by precisely measuring the bleeding volume of the patient.
Blood clotting is a process by which the blood coagulates to form solid masses or clots following a wound or trauma. The ability of blood clotting is typically measured by a technique known as IVY Bleeding Time named after Mr. Ivy. The IVY bleeding Time is a widely used test for bleeding tendency that measures the length of time that bleeding continues after an incision is made in the forearm of a patient. To measure the bleeding time of the patient, a round disc of blotter paper is used. The edge of the disc of blotter paper is applied tangentially to the incision to absorb the blood by capillary action. After an interval of 30 seconds, the disc is rotated to a new contact point so that the small blotches of blood are distributed around the periphery of the blotter paper. Typically, the successive blotches of blood become smaller and smaller. By counting the number of blotches, and dividing the total number of the blotches by 2, one can derive the duration of bleeding in minutes. The duration of bleeding time is normally less than 7 minutes.
With respect to surgical complications and patient safety, the duration of bleeding is not as important as the volume of bleeding. If one could measure the volume of blood lost during an IVY Bleeding Time, then a much more powerful and clinically relevant predictor of excessive surgical bleeding would be provided. For example, just prior to surgery, a medical practitioner would be able to assess the probability that the patient had recently taken an aspirin; and therefore, the risk of surgical bleeding complications could be increased.
Therefore, a substantial need exists in the art to develop a method for measuring not only the bleeding time, but also the blood volume of a patient to ensure patient safety and prevent possible surgical complication.